What ISIS is doing is the exact copy of what Mughals did against Sikh Gurus and followers of Sikhism from 15th century to 18th century. Mughal Empire wanted whole India to be converted to Islam religion. Hindus started converting to Muslim because of fear. Watching hundreds of thousands conversion and the fear for their own life, Hindu religious leaders came and asked for help from Sikh Gurus and his followers. Sikh Gurus stepped up to protect freedom of religion (which was unheard on any corner of the world at that time) and Mughals started the same brutal war crime against Sikhs is exactly what Islamic State in Iraq and Syria (ISIS) is doing today in 21st century.